in general, attribute-value sorts of lists are very difficult to use for
relational operations and result in clumsy inefficient queries, as well
as poor data integrity.
whenever possible common attributes shoudl be stored properly as table
fields. reserve EAV for highly sparse freeform information that could
not have been anticipated at design time. for your example, all cars
have a speed, and do/don't have an airbag, so these should be normal
fields in a table.
--
john r pierce N 37, W 122
santa cruz ca mid-left coast
